This thesis seeks to explore how drug cartels achieved de facto sovereign control over the favelas of Rio de Janeiro between 2000 and 2010, effectively preventing the Brazilian state from guaranteeing the rule of law uniformly throughout national territory. It also investigates the extent to which Brazilian citizens have suffered human rights abuses as a result. Drawing on both primary and secondary evidence, I argue that drug cartels gained sovereignty over these enclaves as a combined result of state weakness and cartel strength. The Brazilian state forfeited these territories a century ago, because it was infrastructurally weak to such an extent that it was unable to systematically penetrate them in order to monopolize violence, enforce laws, and provide public services. The cartels, in turn, exploited the favelas as ideal locations for the transport, repackaging, and sale of drugs. Benefiting from the profits of illicit activities, the gangs transformed into well-armed, bellicose organizations that maintained authority over the communities by performing state-like duties. In due course, organized crime amassed sufficient control over the favelas to thwart most state encroachments. Examining the exceptions, I found that the limited police encroachments were largely rights abusive--save those made by the Pacifying Police Units. State weakness and cartel strength have disjointed the rule of law and undermined democracy in Brazil.